Winter school on Physics with Trapped Charged Particles

Non-Neutral Plasmas in SMall Aspect Ratio Toroidal Electron plasma eXperiment - C

Not scheduled

20m

Ecole de Physique des Houches

Speaker

Mr Lavkesh Lachhvani (Institute for Plasma Research)

Description

Stability, equilibrium and transport of electron plasmas in cylindrical traps have been comprehensively investigated owing to their exceptional confinement properties[1]. In recent times non-neutral plasmas in various toroidal configurations have also raised considerable interest ascribed to the capability of producing equal mass plasmas in such configurations[2], [3]. Investigations of equilibrium, confinement and toroidal effects on non-neutral plasmas are being carried out in several traps [4], [5]. While equilibrium and stability have been theoretically established, fundamental limitation to confinement in toroidal geometries has been predicted to be posed by magnetic pumping transport driven by electron-electron collisions[6]. Present work reports the successful confinement of toroidal electron plasmas for more than a second in SMARTEX-C[7], [8], a SMall Aspect Ratio Toroidal Electron plasma eXperiment in a C-shaped trap. Steady state confinement that outlives single particle toroidal drifts and most non-toroidal losses have now allowed transport studies. Besides, strong toroidal effects gives rise to interesting nonlinear collective dynamics which will be discussed in this paper. [1] T. M. O’Neil, “Plasmas with a single sign of charge (an overview),” Phys. Scr., vol. T59, pp. 341–351, Jan. 1995. [2] H. Saitoh, Z. Yoshida, C. Nakashima, H. Himura, J. Morikawa, and M. Fukao, “Confinement of Pure-Electron Plasmas in a Toroidal Magnetic-Surface Configuration,” Phys. Rev. Lett., vol. 92, no. 25, p. 255005, Jun. 2004. [3] X. Sarasola and T. S. Pedersen, “First experimental studies of the physics of plasmas of arbitrary degree of neutrality,” Plasma Phys. Control. Fusion, vol. 54, no. 12, p. 124008, Dec. 2012. [4] J. P. Marler and M. R. Stoneking, “Confinement Time Exceeding One Second for a Toroidal Electron Plasma,” Phys. Rev. Lett., vol. 100, no. 15, p. 155001, Apr. 2008. [5] P. Zaveri, P. I. John, K. Avinash, and P. K. Kaw, “Low-aspect-ratio toroidal equilibria of electron clouds,” Phys. Rev. Lett., vol. 68, no. 22, pp. 3295–3298, Jun. 1992. [6] S. M. Crooks and T. M. O’Neil, “Transport in a toroidally confined pure electron plasma,” Phys. Plasmas, vol. 3, no. 7, pp. 2533–2537, Jul. 1996. [7] S. Pahari, H. S. Ramachandran, and P. I. John, “Electron plasmas: Confinement and mode structure in a small aspect ratio toroidal experiment,” Phys. Plasmas, vol. 13, no. 9, p. 092111, 2006. [8] L. Lachhvani, S. Pahari, and Y. C. Saxena, “Achieving ultra high vacuum conditions in SMARTEX-C: control of instabilities and improved confinement,” J. Phys. Conf. Ser., vol. 390, p. 012047, Nov. 2012.